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Beyond the Headlines: Relative Energy Deficiency in Sport (RED-S) and its impact on Fertility


RED-S… Have you heard of it?


Jonny has been talking about it for years: (see: https://www.ldnphysio.co.uk/post/red-s-relative-energy-deficiency-in-sport).

 

But it’s also been brought to the attention of the media more recently, with athletes such as Laura Kenny, Laura Cain and Evie Richards discussing either their direct experience or experience through others.



Laura Kenny interview on RED-S and pregnancy


Whilst RED-S is commonly a condition associated with elite athletes,  it’s now a condition we know that can effect ANYONE who is active, irrelevant of gender, age, sport, body shape OR size.


(In this blog, I will be referring to ‘male’ and ‘female’ in relation to those with male or female reproductive anatomy and sex hormones).  


To make things simple, it is where your body does not have sufficient energy to meet the demands of exercise AND daily functions (like growing, breathing and digesting). Common examples are through restricting food / calorie consumption, underestimating the energy requirements of exercise, or changes to training (such as changing intensity, frequency or poor timing of energy intake).    


Long term energy deficiency can put us at risk of long term physical AND mental health conditions, as well as potentially impacting athletic potential. We also know it can have long term negative effects on an individual’s fertility. This can affect males and females – however the outcome and effects are more widely acknowledged in females.


To make things simple, it is where your body does not have sufficient energy to meet the demands of exercise AND daily functions (like growing, breathing and digesting).

 

So let’s kick off and get into the science behind it…

 

When you are not getting enough energy input to match your energy output, it affects your hypothalamus. Our hypothalamus is an almond sized bit of your brain, right in the middle. It’s your body’s organiser (think of it like your head coach or team manager), it directly affects and communicates with your autonomic nervous system by affecting the hormones in your body.


( A quick reminder of the relevant hormones: we specifically refer to these hormones as “gonadotropins” – in females these are FSH (Follicle Stimulating Hormone) and LH (Lutenising Hormone). In males, it is testosterone. )


In females, FSH causes the ovaries to ripen the egg and helps produce oestrogen, whilst LH triggers the release of the egg from the ovaries (ovulation). In males, testosterone is the key sex hormone, responsible for sperm production, libido and sexual function (as well as muscle mass, fat distribution, mood, metabolism… yeah, testosterone is pretty important).


Low energy availability can suppress how much gonadotropins your hypothalamus releases:


In females, less LH and FSH means that your egg can’t ripen or be released from the ovaries, as a result, the ovaries produce less oestrogen. This can affect the whole cycle, causing less periods (oligomenorrhoea) or absence of periods (amenorrhea). Disruption to the function of your hypothalamus resulting in absent periods is called “Functional Hypothalamic Amenorrhea” (FHA). (If you want a refresher on female hormones, see my last blog post).


In males, it’s a bit more difficult to notice (as, of course, males don’t have periods), however reduced sexual desire or erectile dysfunction can be signs of RED-S. Other symptoms in females AND males can be fatigue, decreased muscle mass, mood swings, sleep disturbance, cognitive changes and reduced motivation.

 

In the short term, if an egg is not released from the ovaries – then it can’t get fertilised to enable pregnancy (in simple terms, no periods = no pregnancy). Obviously, low libido and reduced sexual function also means it’s harder for males to perform pregnancy enabling acts… (you get this gist).

 

The longer term effects of reduced hormones are better explored and evidenced in females. FHA is referred to as functional – because there is no structural or physical abnormality. It’s a disruption to the hypothalamus’ normal job role (e.g. the team manager has been given a 3 match ban). Ideally if you change the behaviours resulting in the absence/missing periods (chill out Jose!) – previous hormone levels return and it is reversible. Therefore, the periods return (and there is an improved chance of pregnancy).

 

HOWEVER, what happens if FHA is sustained and changes are not made?

 

Prolonged FHA can lead to long term alterations to the lining of the endometrium, reduced ovarian function and reduced cervical mucus production (which helps transport the sperm). Some of these changes present similarly to females who have gone through the menopause. In males, prolonged reduced levels of testosterone can reduce sperm quality and semen parameters.


So whilst chances of pregnancy improve with a return of menstrual function in females (and normal hormone levels), it doesn’t mean fertility has returned to normal (given the potential for longer term effects), there is also some evidence to suggest that having had FHA in females can increase your risk of pregnancy related complications including miscarriage. There is not yet the same detail or level of evidence in the long-term effects for males.


HOWEVER, it is important to acknowledge, the impact of FHA on fertility differs among individuals - some females can still conceive and give birth despite long term amenorrhea.  Many males also recover from RED-S without long term fertility issues.


So whilst chances of pregnancy improve with a return of menstrual function in females (and normal hormone levels), it doesn’t mean fertility has returned to normal (given the potential for longer term effects). There is also some evidence to suggest that having had FHA in females can increase your risk of pregnancy related complications including miscarriage.

 

RED-S can be scary and overwhelming, however, help is out there. If you think you or someone you know might be suffering from RED-S, then reach out to a Healthcare professional. The sooner you get support, the quicker and better the recovery.


If you feel you may have some of the symptoms or tendencies pointing to RED-S, The RED-S clinic is our specialist clinic and can be found at www.ldnphysio.co.uk/reds-clinic. Alternatively you can simply book a Physiotherapy appointment with one of our specialists, who can support with your diagnosis and tailored treatment plan.



 

 

If you want to read a bit more around RED-S, here are some useful links:

 

You’ll also find the recent interview with Laura Kenny here:

 


Physiotherapist and patient having a conversation at LDN PHYSIO Old Street clinic


References:


Dipla K, Kraemer RR, Constantini NW, Hackney AC. (2021). Relative energy deficiency in sports (RED-S): elucidation of endocrine changes affecting the health of males and females. Hormones (Athens).. 20(1), pp.35 - 47.


Shufelt CL, Torbati T, Dutra E. (2017). Hypothalamic Amenorrhea and the Long-Term Health Consequences.. Semin Reprod Med.. 35(3), pp.256 - 262.


Mountjoy M, Sundgot-Borgen JK, Burke LM, Kathryn EA. (2018). IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. BMJ. 52(11), pp.687-697.


Burke LM, Close GL, Lundy B, Mooses M, Morton JP, Tenforde AS. (2018). Relative Energy Deficiency in Sport in Male Athletes: A Commentary on Its Presentation Among Selected Groups of Male Ath. Int J Sport Nutr Exerc Metab.. 28(4), pp.364-374.

 

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